The problem with winter cruising on a charter is that you are by definition on a schedule. I’ve had some of my best days on the water in the winter. I’ve also wound up in a gale with 40 knot winds and 7+ foot breaking seas within 5 miles of Friday Harbor trying to get home after avoiding the winds for 4 days, but with just a slight unexpected shift in wind direction I was suddenly fully exposed instead of protected.
Winter here, by definition, is often unpredictable and unstable weather. On my own boat, I can find the short windows in the weather to take advantage of. Showing up on a planned week for a charter, hoping for good luck, is in my opinion asking for trouble. Low probability, high risk.
Plus, during the winter, lots of things are closed, towns are not as much fun. It’s more for locals to enjoy than tourists. Nothing worse than being cold and wet, stuck on the flybridge for visibility in rain and fog in an area you don’t know like the back of your hand.
Truthfully, good chance you would have a good time, but if you DID have a bad time, it would likely be epic bad. Not the kind you cherish and laugh about later, the kind you don’t talk about and just never repeat.